Systems and methods for bonding semiconductor elements

ABSTRACT

A bonding machine for bonding semiconductor elements, the bonding machine including: a support structure for supporting a substrate; a bond head assembly, the bond head assembly including a bonding tool configured to bond a plurality of semiconductor elements to the substrate; an alignment structure including first alignment markings; an alignment element configured to be placed on the alignment structure using the bonding tool, the alignment element including second alignment markings; an imaging system configured to image relative positions of the first alignment markings and corresponding ones of the second alignment markings; and a computer system configured to provide an adjustment to a position of at least one of the bonding tool and the support structure during bonding of ones of the plurality of semiconductor elements to the substrate, the computer being configured to provide the adjustment at least partially based on the relative positions of the first alignment markings and the corresponding ones of the second alignment markings, the adjustment being specific to bonding of the ones of the plurality of semiconductor elements to a corresponding region of the substrate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/553,049, filed Nov. 25, 2014, which claims the benefit of U.S.Provisional Patent Application No. 61/911,226 filed Dec. 3, 2013, thecontent of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the formation of semiconductorpackages, and more particularly, to improved systems and methods forbonding semiconductor elements to bonding locations.

BACKGROUND OF THE INVENTION

In certain aspects of the semiconductor packaging industry,semiconductor elements are bonded to bonding locations. For example, inconventional die attach applications (also known as die bonding), asemiconductor die is bonded to a bonding location (e.g., a leadframe,another die in stacked die applications, a spacer, etc.). In advancedpackaging applications (e.g., flip chip bonding, thermocompressionbonding), semiconductor elements (e.g., bare semiconductor die, packagedsemiconductor die, etc.) are bonded to bonding locations, withconductive structures (e.g., conductive bumps, contact pads, solderbumps, conductive pillars, copper pillars, etc.) disposed therebetween.

It is desirable that bonding machines (e.g., thermocompressive bondingmachines, thermosonic bonding machines, ultrasonic bonding machines,etc.) be configured to accurately place and bond a semiconductor elementto a bonding location. However, various inaccuracies and error sourcesexist in such bonding machines. Such inaccuracies and error sources arenot identical from machine to machine, or from application toapplication. This results in challenges to the machine user and/oroperator to consistently and accurately place and bond semiconductorelements.

Thus, it would be desirable to provide improved systems for, and methodsof, bonding semiconductor elements to bonding locations.

SUMMARY OF THE INVENTION

According to an exemplary embodiment of the present invention, a bondingmachine for bonding semiconductor elements includes: (1) a supportstructure for supporting a substrate; (2) a bond head assembly, the bondhead assembly including a bonding tool configured to bond a plurality ofsemiconductor elements to the substrate; (3) an alignment structureincluding first alignment markings; (4) an alignment element configuredto be placed on the alignment structure using the bonding tool, thealignment element including second alignment markings; (5) an imagingsystem configured to image relative positions of the first alignmentmarkings and corresponding ones of the second alignment markings; and(6) a computer system configured to provide an adjustment to a positionof at least one of the bonding tool and the support structure duringbonding of ones of the plurality of semiconductor elements to thesubstrate, the computer being configured to provide the adjustment atleast partially based on the relative positions of the first alignmentmarkings and the corresponding ones of the second alignment markings,the adjustment being specific to bonding of the ones of the plurality ofsemiconductor elements to a corresponding region of the substrate.

According to another exemplary embodiment of the present invention, amethod of operating a bonding machine is provided. The bonding machineincludes a bonding tool configured to bond a semiconductor element to asubstrate. The method includes the steps of: (a) providing an alignmentstructure on the bonding machine, the alignment structure including aplurality of first alignment markings; (b) selecting an area of thealignment structure based on a region of the substrate to be bonded withthe semiconductor element, the substrate configured to be supported by asupport structure of the bonding machine; (c) imaging ones of secondalignment markings on an alignment element along with ones of the firstalignment markings on the area of the alignment structure; and (d)adjusting a position of at least one of the bonding tool and the supportstructure during a subsequent bonding process using information providedfrom step (c).

According to another exemplary embodiment of the present invention, amethod of bonding a plurality of semiconductor elements to a substratewith a bonding tool is provided. The method includes the steps of: (a)placing an alignment element over each of a plurality of areas of analignment structure, each of the plurality of areas corresponding to oneof a plurality of regions of a substrate supported by a supportstructure; (b) determining an offset of the alignment element withrespect to each of the plurality of areas; and (c) adjusting a positionof at least one of (1) the bonding tool and (2) the support structureduring bonding of a plurality of semiconductor elements to each of theplurality of regions of the substrate, the position adjustment for eachof the plurality of regions being related to the offset determined forthe area corresponding to each of the plurality of regions.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is best understood from the following detailed descriptionwhen read in connection with the accompanying drawings. It is emphasizedthat, according to common practice, the various features of the drawingsare not to scale. On the contrary, the dimensions of the variousfeatures are arbitrarily expanded or reduced for clarity. Included inthe drawings are the following figures:

FIG. 1A is a block diagram top view of a portion of a bonding machinefor bonding semiconductor elements to a substrate in accordance with anexemplary embodiment of the present invention;

FIGS. 1B-1C are block diagrams of alternate structures for a portion ofthe bonding machine of FIG. 1A;

FIG. 2A is an block diagram top view of a substrate and an alignmentstructure of a bonding machine in accordance with an exemplaryembodiment of the present invention;

FIG. 2B is a detailed view of a portion of the alignment structure ofFIG. 2A;

FIG. 2C is a detailed view of a portion of FIG. 2B;

FIG. 3A is an block diagram top view of the apparatus of FIG. 2A with analignment element disposed on the alignment structure, in accordancewith an exemplary embodiment of the present invention;

FIGS. 3B-3E are top views of various alignment elements placed over aportion of the alignment structure illustrated in FIG. 3A in accordancewith various exemplary embodiments of the present invention;

FIG. 3F is a top view of the alignment element of FIG. 3E;

FIG. 3G is a detailed view of portion 3G of FIG. 3E;

FIG. 3H is a detailed view of portion 3H of FIG. 3F;

FIG. 4A is a block diagram top view of the apparatus of FIG. 2A with amisaligned alignment element disposed on the alignment structure, inaccordance with an exemplary embodiment of the present invention;

FIG. 4B is a detailed top view of the misaligned alignment element ofFIG. 4A;

FIG. 5A is another block diagram top view of the apparatus of FIG. 2Awith another misaligned alignment element disposed on the alignmentstructure, in accordance with an exemplary embodiment of the presentinvention;

FIG. 5B is a detailed top view of the misaligned alignment element ofFIG. 5A;

FIG. 6A is a partial sectional block diagram view of portions of thebonding machine of FIG. 1A in accordance with an exemplary embodiment ofthe present invention; and

FIG. 6B is a partial sectional block diagram view of portions of anotherbonding machine in accordance with an exemplary embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “semiconductor element” is intended to refer toany structure including (or configured to include at a later step) asemiconductor chip or die. Exemplary semiconductor elements include abare semiconductor die, a semiconductor die on a substrate (e.g., aleadframe, a PCB, a carrier, a semiconductor wafer, a BGA substrate,etc.), a packaged semiconductor device, a flip chip semiconductordevice, a die embedded in a substrate, a stack of semiconductor die,amongst others. Further, the semiconductor element may include anelement configured to be bonded or otherwise included in a semiconductorpackage (e.g., a spacer to be bonded in a stacked die configuration, asubstrate, an interposer, etc.).

In accordance with certain exemplary embodiments of the presentinvention, if an alignment element placed using a bonding tool ismisaligned with a portion of a bonding machine alignment structure overwhich it is placed (where misalignment is determined, for example, usingpredetermined criteria such as a predetermined degree of misalignment),positions of a bonding tool (and/or a support structure of a substrate)are adjusted, based upon the misalignment, during bonding ofsemiconductor elements to bonding locations in a corresponding region(e.g., a row of bonding locations) of the substrate. An imaging systemimages the alignment element over the portion of the alignment structureand the misalignment is determined based upon the image(s) using acomputer system of the bonding machine. Such adjustment provides forimproved bonding accuracy as compared to conventional methods.

As will be appreciated by those skilled in the art, a thermocompressionbonding machine (such as machine 100 in FIG. 1A, or any of the othermachine embodiments described herein) may include many elements notshown in the drawings herein for simplicity. Exemplary elements include,for example: input elements for providing input workpieces (i.e.,substrates) to be bonded with additional semiconductor elements; outputelements for receiving processed workpieces that now include additionalsemiconductor elements; transport systems for moving workpieces; imagingsystems for imaging and alignment of workpieces; a bond head assemblycarrying the bonding tool; a motion system for moving the bond headassembly; a computer system including software for operating themachine; amongst other elements.

FIG. 1A illustrates portions of bonding machine 100 (e.g., athermocompressive bonding machine, a thermosonic bonding machine, anultrasonic bonding machine, etc.) including support structure 102 (e.g.,a shuttle, a heated shuttle, a heat block, an anvil, etc.) and alignmentstructure 104. Alignment structure 104 is secured to (either directly orindirectly), or integrated with, support structure 102. Thus, whensupport structure 102 moves (e.g., along the x-axis shown in FIG. 1A, orin any other direction as desired) alignment structure 104 moves withsupport structure 102.

Bonding machine 100 also includes bond head assembly 106 (illustrated asmoving along the y and z axes—see the legend, as well as about a theta(θ) axis—but may move in other directions, as desired), semiconductorelement source 108 (e.g., a semiconductor wafer), and pick tool 110(illustrated as moving along the x axis—but may move in otherdirections, as desired). In an exemplary operation, pick tool 110removes a semiconductor element (e.g., a bare die) from source 108. Picktool 110, with the semiconductor element, moves along the x-axis to atransfer position (not shown). Bond head assembly 106 also moves to thetransfer position, where the semiconductor element is transferred frompick tool 110 to a place tool (e.g., a bonding tool 106 a, not shown inFIG. 1A, but see FIG. 6A) carried by bond head assembly 106. Supportstructure 102 is aligned in a given position along its x-axis range ofmotion (e.g., see the dash-line position of support structure 102 andalignment structure 104 along the x-axis). Bond head assembly 106 movesalong the y-axis to a position above a bonding location of a substratesupported by support structure 102. Bond head assembly 106 is loweredalong the z-axis such that the bonding tool is able to bond thesemiconductor element to the bonding location of the substrate. Thisprocess may be repeated such that a number of semiconductor elementsfrom semiconductor element source 108 may be bonded to respectivebonding locations on the substrate. Bonding machine 100 also includesimaging system 174 (illustrated as moving along the x and y axes—but maymove in other directions, as desired) and computer system 176. As willbe appreciated by those skilled in the art, imaging system 174 (e.g.,including at least one camera) is configured for use in determiningproper placement and alignment of the semiconductor elements torespective bonding locations on the substrate as will be describedherein. Computer system 176 obtains information from imaging system 174,and determines any adjustment of the bonding tool and/or the supportstructure position as set forth herein (e.g., using algorithms and thelike).

The directions of motion (e.g., along x, y, and z-axes, and rotationabout the theta (θ) axis) shown in FIG. 1A (and the other drawingsherein) are exemplary in nature. Additional or different motion axes ordirections may be utilized by the various elements. For example, FIG. 1Aillustrates an exemplary configuration where support structure 102 movesalong an x-axis, and wherein alignment structure 104 is positioned on anend of support structure 102 along this x-axis. Of course, alternativeconfigurations are contemplated. In FIG. 1B, support structure 112 movesalong a y-axis (and bond head assembly 116 moves along an x-axis, az-axis, and about a theta (θ) axis), and alignment structure 118 ispositioned on an end of support structure 112 along this y-axis. In FIG.1C, two different alignment structures 124, 128 secured to (eitherdirectly or indirectly), or integrated with, support structure 122, areprovided. Support structure 122 moves along an x-axis (and bond headassembly 126 moves along an a y-axis, a z-axis, and about a theta axis),and alignment structure 124 is positioned on an end of support structure122 along this x-axis. Another alignment structure 128 is positioned onanother end of support structure 122 along a y-axis as illustrated.

FIG. 2A is a detailed partial view of substrate 296 supported by supportstructure 102 (support structure 102 is not visible in FIG. 2A, but seeFIG. 1A). Substrate 296 (e.g., a leadframe, a semiconductor wafer, a BGAsubstrate, etc.) includes a plurality of rows and columns of bondinglocations. More specifically, exemplary substrate 296 includes 50columns (i.e., columns 201, 202, 203, 204, 205, 206, 207, 208, . . . ,250) and 8 rows (i.e., rows a, b, c, d, e, f, g, and h) for a total of400 bonding locations. At the intersection of each row and column is abonding location marked by the relevant row (e.g., a, b, c, etc.). Eachof the bonding locations may be a portion of a substrate (e.g., aportion of a leadframe, a chip location on a wafer, a chip location onanother substrate, etc.), or a semiconductor element (e.g., a die)configured to receive another semiconductor element bonded thereto(e.g., in a stacked die configuration), or any other type of bondinglocation configured to receive a semiconductor element. Alignmentstructure 104 includes first alignment markings 270, a portion of whichare labelled 270 a.

FIG. 2B is a detailed view of portion 270 a of first alignment markings270. Portion 270 a includes 7 columns (i.e., columns 201′, 202′, 203′,204′, 205′, 206′, and 207′) and 7 rows (i.e., rows a, b, c, d, e, f, andg) of first alignment markings 270. For example, a first alignmentmarking (labeled “2C” in FIG. 2B) is at the intersection of column 202′and row g and is illustrated in greater detail in FIG. 2C. As will beappreciated by those skilled in the art, each of the first alignmentmarkings 270 (including the marking detailed in FIG. 2C) may actually bea plurality of markings. For example, FIG. 2C illustrates that thesingle marking labelled “2C” in FIG. 2B is actually a plurality ofmarkings arranged in 7 columns (i.e., columns 201″, 202″, 203″, 204″,205″, 206″, and 207″) and 7 rows (i.e., rows a, b, c, d, e, f, and g).

In FIG. 3A, alignment element 364 (e.g., a transparent glass die) hasbeen placed on an area of alignment structure 104 (i.e., the areaincluding portion 270 a of first alignment markings 270). For example, abonding tool (e.g., a place tool) carried by bond head assembly 106places alignment element 364 on a designated area of alignment structure104. More specifically, an alignment element (such as element 364) maybe placed on different locations of alignment structure 104. Thedifferent locations are selected, for example, based on a correspondingregion of a substrate (e.g., such as a row of bonding locations ofsubstrate 296). As noted above, alignment element 364 may be transparent(e.g., glass) (or at least translucent) to facilitate imaging of therespective alignment markings on alignment structure 104. Morespecifically, if the alignment element 364 is transparent (or at leastpartially translucent) then the second alignment markings on element 364may be imaged (e.g., using imaging system 174) with respect to arespective portion of the first alignment markings on alignmentstructure 104.

In the example illustrated in FIG. 3A, and in connection with bondingsemiconductor elements in row “a” of substrate 296—it may be desirableto determine if an adjustment needs to be made to the locations of thebonding tool and/or support structure when bonding respectivesemiconductor elements to bonding locations 201 a-250 a in row “a”. Thatis, certain errors (e.g., positioning of the bonding tool) may be common(or at least partially common) to each row “a”-“h”. Therefore, analignment may be performed for each such row (or other region) ofbonding locations. Following such an alignment, an adjustment (e.g., anadjustment to the x, y, or theta (θ) positioning of the bonding tooland/or the support structure) specific to the region (e.g., row) may bemade when bonding semiconductor elements to that region (row) of thesubstrate. In this regard, a portion of alignment markings 270 onalignment structure 104 are selected corresponding to each region.Referring again to FIG. 3A, a center point of row “a” of substrate 296is in line with a location of alignment structure 104 (e.g., see arrow358). For example, the center point of row “a” is substantially in linewith row “d” of portion 270 a (e.g., see FIG. 3B) of first alignmentmarkings 270. In such an example, row “d” of portion 270 a may beselected as the closest row of portion 270 a that aligns with the centerpoint of row “a” of substrate 296. That is, when alignment element 364is placed on alignment structure 104 (during the process of determiningadjustments that may be made for row “a”) it is placed as shown in FIGS.3A-3B to determine if the alignment between ones of first alignmentmarkings 270 a and the second alignment markings on alignment structure364 is adequate. For example, such placement may be made using a knowncoordinate system of the machine and machine placement system. If thealignment is not within a predetermined tolerance (e.g., as determinedin the specific application using an algorithm in memory of computersystem 176) then an adjustment may be determined when bondingsemiconductor elements to bonding locations in row “a”.

FIG. 3B is a detailed view of alignment element 364 placed on alignmentstructure 104 as shown in FIG. 3A. As shown in FIG. 3B, cross-shapedalignment markings 364 a, 364 b of alignment element 364 (referred toherein as second alignment markings) are aligned with respective ones offirst alignment markings 270 (specifically, aligned with the center ofcircles 207′a, 201′g) within portion 270 a of alignment structure 104.As shown in FIG. 3B there is substantial alignment (e.g., as determinedby software of computer system 176 by processing image data provided byimaging system 174) and no adjustment needs to be made during bondingfor any of the bonding locations 201 a-250 a (in row “a” of FIG. 3A).

Alignment element 364 may be stored in a location, for example,proximate, or on, bond head assembly 106 during bonding operations. Sothe bonding tool may then return alignment element 364 to that location.The bonding tool may then obtain semiconductor elements from pick tool110 at the transfer position (see, e.g., FIG. 1A), and bond thesemiconductor elements to respective bonding locations 201 a-250 a (orany portions thereof) with any positional correction being applied tobond head assembly 106 (and thus the bonding tool) and/or supportstructure 102 for each bond. Again, in this example, there would be zerocorrection during bonding along row “a” of FIG. 3A. The alignment andbonding processes described above may be repeated for each subsequentrow “b”-“h” of FIG. 3A, with any positional correction for each rowapplied by the bonding tool (e.g., using bond head assembly 106) and/orsupport structure 102 before bonding semiconductor elements to thatrow's bonding locations (e.g., 201 b-250 b for row “b”, 201 c-250 c forrow “c”, etc.).

FIGS. 3C-3D illustrate other exemplary alignment elements 362, 360 ofdecreasing size that may correlate to the size of bonding locations(e.g, 201 a-250 h) and/or the size of the semiconductor elements to bebonded to such bonding locations. Specifically, alignment element 362,illustrated in FIG. 3C over a portion of first alignment markings 270,includes second alignment markings 362 a, 362 b at opposing cornersthereof (i.e., over first alignment markings 206′b, 202′f,respectively). Smaller alignment element 362 overlies a 5×5 grid offirst alignment markings as compared to the 7×7 grid of first alignmentmarkings illustrated in FIG. 3B. Smallest alignment element 360illustrated in FIG. 3D over a portion of first alignment markings 270,includes second alignment markings 360 a, 360 b at opposing cornersthereof (i.e., over first alignment markings 205′c, 203′e,respectively), and overlies a 3×3 grid of first alignment markings. Byproviding various different alignment elements (e.g., elements 360, 362,364) with different sizes and/or alignment marking configurations, it isclear that varying applications (e.g., bonding of semiconductor elementsof varying sizes) may be accommodated.

While FIGS. 3B, 3C, and 3D illustrate three distinct alignment elementswith specific alignment marking configurations, it is possible toaccommodate varying applications with a single alignment element. Forexample, FIG. 3E illustrates alignment element 366 placed over a portion270 a of first alignment markings 270 of alignment structure 104.Alignment element 366 includes, in effect, three series of secondalignment marking pairs 366 a, 366 a′; 366 b, 366 b′; 366 c, 366 c′.Thus, alignment element 366 could be used in connection with threedifferent configurations of devices, essentially replacing the need forusing distinct alignment elements 360, 362, and 364 with a singlestructure. Of course, this is simply an illustration of the broaderintent, that is, a single alignment element may be used with a pluralityof sets of alignment markings for a plurality of applications. FIG. 3Fillustrates alignment element 366 away from markings 270 a of alignmentstructure 104.

First alignment markings 270, and second alignment markings (e.g.,markings 360 a, 360 b, 362 a, 362 b, 364 a, 364 b, 366 a-366 c, and 366a′-366 c′) as illustrated herein are exemplary in nature. That is, themarkings are not limited to the style shown and described herein, thenumber shown and described herein, or the orientation shown anddescribed herein. In practice, the first and second alignment markingsmay be very different than those shown and described with respect to,for example, FIGS. 3B-3E. For example, each of the markings included ingroup 270 a may actually include a plurality of markings. As providedabove, in a specific example, the single mark labelled “2C” in FIG. 2Bactually represents the group of markings shown in FIG. 2C. Likewise,each of the second alignment markings (e.g., 366 a, 366 a′, 366 b, 366b′, 366 c, 366 c′) may also represent a group of markings. Thus, it isunderstood that in FIG. 3B (and in other drawings herein) that theactual alignment of second alignment markings 364 a, 364 b with ones ofthe first alignment markings included in group 270 a is illustrative andmay not actually represent the actual alignment. That is, it illustratesthat the markings (whatever they actually represent) are aligned. Thispoint is further illustrated below by reference to FIGS. 3G-3H.

FIG. 3G is a detailed view of the portion of FIG. 3E labeled “3G”, andFIG. 3H is a detailed view of the portion of FIG. 3F labelled “3H”. InFIG. 3E, the second alignment marking 366 a′ is shown as a cross-shapedmarking centered over one of circular alignment markings 270 included ingroup 270 a. In the detailed view of FIG. 3H, second alignment marking366 a′ is actually a group of 4 X-shaped markings 366 a′1, 366 a′2, 366a′3, and 366 a′4 (referred to herein as third alignment markings). Thus,the cross-shaped marking 366 a′ is just a representation of the actualmarking which is a group of third alignment markings 366 a′1, 366 a′2,366 a′3, and 366 a′4. Likewise, the circular alignment marking of group270 a (labelled as “3G” in FIG. 3E) is actually a group of rectangularshapes (referred to herein as fourth alignment markings) shown in FIG.3G (i.e., where the group includes 7 rows and 7 columns of rectangles;with 3 rows labelled as a, d, and g; and 3 columns labelled as 201″,204″, and 207″). Thus, FIG. 3G actually illustrates four third alignmentmarkings 366 a′1, 366 a′2, 366 a′3, and 366 a′4 aligned with four fourthalignment markings 204″a, 201″d, 204″g, and 207″d. This is a moredetailed way of illustrating what is shown in detail “3G” of FIG.3E—that is, second alignment marking 366 a′ is properly aligned with thecorresponding first alignment marking.

In contrast to FIG. 3A (which illustrates a properly aligned alignmentelement 364 over markings 270 a), FIG. 4A and FIG. 5A illustrateexamples where the respective alignment element is not properly aligned,thereby resulting in an adjustment to the bonding tool and/or thesupport structure when bonding devices in that region (e.g., the row ofbonding locations). Referring specifically to FIG. 4A, alignment element364 has been placed over alignment structure 104 by the bonding tool (orplace tool) in, what bonding machine 100 has been taught, is an alignedposition over portion 270 a of first alignment markings 270corresponding to row “a” of the bonding locations. However, asillustrated in FIG. 4A, and more clearly seen in FIG. 4B, alignmentelement 364 is in a misaligned position. As illustrated in FIG. 4B,misaligned alignment 364 is shown in solid-line, while the properlyaligned position is shown in dashed-line and is labelled as 364′. Inthis example, alignment structure 364 is misaligned in both anx-direction and a y-direction as determined using an image(s) providedby an imaging device (e.g. a camera) of imaging system 174 positionedover actual alignment element 364. Through image processing (e.g., usingsoftware installed on computer system 176) it is determined that thesecond alignment markings (i.e., the cross-shaped symbols shown in FIG.4B) of alignment element 364 are misaligned from the corresponding onesof first alignment markings 270 (i.e., the circular shaped symbols shownin FIG. 4B). Thus, it is determined that alignment element 364 ismisaligned by an amount shown as “x1” in the x-axis direction, and by anamount shown as “y1” in the y-axis direction. Computer system 176calculates or otherwise determines (e.g., using algorithms or the like)adjustments to be made to (1) the bonding tool position through bondhead assembly 106 (e.g., an offset equal to an adjustment of y1 alongthe y-axis), and support structure 102 (e.g., an offset equal to anadjustment of x1 along the x-axis), to properly place and align (and tosubsequently bond) the semiconductor elements from semiconductor elementsource 108 on bonding locations 201 a-250 a within row “a”. Thisprocedure may then be repeated for each subsequent bonding location row“b”-“h” to be bonded with adjustments made, if needed, in each bondingrow to be bonded (e.g, 201 b-250 b, 201 c-250 c, . . . 201 h-250 h).

Referring specifically to FIG. 5A, alignment element 364 has been placedover alignment structure 104 by the bonding tool. As illustrated in FIG.5A, and more clearly seen in FIG. 5B, alignment element 364 is in amisaligned position. As illustrated in FIG. 5B, misaligned alignment 364is shown in solid-line, while the properly aligned position is shown indashed-line and is labelled as 364′. In this example, alignmentstructure 364 is misaligned in an x-direction, a y-direction, and abouta theta (θ) axis as determined using an image(s) provided by an imagingdevice (e.g. a camera) of imaging system 174 positioned over actualalignment element 364. Through image processing (e.g., using softwareinstalled on computer system 176) it is determined that the secondalignment markings (i.e., the cross-shaped symbols shown in FIG. 5B) ofalignment element 364 are misaligned from the corresponding ones offirst alignment markings 270 (i.e., the circular shaped symbols shown inFIG. 5B). Thus, it is determined that alignment element 364 ismisaligned by an amount shown as “x1” in the x-axis direction, by anamount shown as “y1” in the y-axis direction, and by an amount shown asθ1 about the theta (θ) axis. Computer system 176 calculates or otherwisedetermines (e.g., using algorithms or the like) adjustments to be madeto (1) the bonding tool position through bond head assembly 106 (e.g.,an offset equal to an adjustment of y1 along the y-axis, and θ1 aboutthe theta axis), and (2) support structure 102 (e.g., an offset equal toan adjustment of x1 along the x-axis), to properly place and align (andto subsequently bond) the semiconductor elements from semiconductorelement source 108 on bonding locations 201 a-250 a within row “a”. Thisprocedure may then be repeated for each subsequent bonding location row“b”-“h” to be bonded with adjustments made, if needed, in each bondingrow to be bonded (e.g, 201 b-250 b, 201 c-250 c, . . . 201 h-250 h).

FIG. 6A illustrates portions of bonding machine 100 (previouslyillustrated and described with respect to FIG. 1A, but with certainadditional elements shown, and with certain elements removed, in FIG.6A). Bonding machine 100 includes bond head assembly 106 (carryingbonding tool 106 a which has placed alignment element 364 on alignmentstructure 104) and support structure 102 (supporting substrate 296).Substrate 296 has been illustrated and described above with respect toFIGS. 2A, 3A, 4A, and 5A. Alignment structure 104 (illustrated withadditional detail compared to the prior drawings) is supported byunderlying support bracket 602 so as to move with support structure 102along its motion axis (or axes). Alignment structure 104 defines trench604 and includes alignment marking structure 104 a (while shown asseparate elements in FIG. 6A, it is understood that alignment markingstructure 104 a may be integrated with the remainder of alignmentstructure 104 as a single structure). The upper surface of alignmentmarking structure 104 a (which includes first alignment markings 270thereon) is below the top of trench 604. Alignment element 364 (e.g., aglass die, shown in dotted lines) is placed over alignment structure 104and held in place by a holding force provided by holding system 600(e.g, a vacuum source providing a vacuum force, a magnetic sourceproviding a magnetic force, etc.) pulling down and holding alignmentelement 364 in place on a top surface of alignment structure 104. Thelower surface of alignment element 364 (e.g., having second alignmentmarkings 364 a, 364 b thereon) is spaced apart from the upper surface ofmarking structure 104 a, with second alignment markings 364 a, 364 baligned (e.g., as shown in FIGS. 3A, 4A, and 5A) with a respectiveportion of first alignment markings 270. Alignment element 364 isdesirably transparent (or at partially transparent or translucent) tofacilitate imaging the second alignment marks 364 a, 364 b and therespective ones of first alignment markings 270 (along a z-axis) usingimaging system 174 (e.g., see FIG. 1A). This alignment information isprocessed by computer system 176 (e.g., see FIG. 1A) as described above.

Of course, the illustration of bonding machine 100 in FIG. 6A (as wellas the other drawings shown herein) are exemplary in nature, and manychanges may be made as desired in the specific application within thescope of the present invention. One change that may be made relates tosupport structure 102. As described above, support structure 102 maytake various configurations such as a shuttle, a heated shuttle, a heatblock, an anvil, etc. FIG. 6B illustrates bonding machine 100 a (withlike elements having the same reference numbers) which is different frombonding machine 100 shown in FIGS. 1A and 6A, primarily with respect tothe support structure.

In FIG. 6B, support structure 102 a includes application specific chuck606 (which may be heated), fine x-axis motion system 608, and shuttle610. In the illustrated embodiment, shuttle 610 is configured to be the“coarse” x-axis motion system, while motion system 608 (carried byshuttle 610) is a “fine” x-axis motion system. Motion system 608 carrieschuck 606. Thermal insulator 612 separates chuck 606 (as well assubstrate 296) from alignment structure 104 to prevent/minimize heattransfer therebetween.

As provided above (e.g., in connection with FIG. 1A) the specific motionsystems of the various elements may vary widely. In one embodiment(shown in FIG. 1A) bond head assembly 106 moves along the y-axis andabout the 0-axis (theta). In this embodiment, motion along the x-axis isprovided by support structure 102 (and in the case of FIG. 6B, by eitherof motion system 608 and/or shuttle 610, of support structure 102 a).Thus, in order to make an adjustment (e.g., as determined by theprocesses described herein such as the x-axis, y-axis, and θ-axisadjustments determined to be needed in FIG. 5B) the corresponding motionsystem can make the adjustment. Referring to the adjustments mentionedabove in connection with FIG. 5B, bond head assembly 106 may make they-axis and θ-axis adjustment, while support structure 102 (or supportstructure 102 a in FIG. 6B, such as through motion system 608) may makethe x-axis adjustment.

As will be appreciated by those skilled in the art, an exemplary machinearchitecture has been described herein, wherein adjustments to thex-axis are made through motion of the support structures describedherein (including but not limited to motion of fine x-axis motion system608 in FIG. 6B), while adjustments to the y-axis or theta axis are madeby the bond head assembly. However, this is just an exemplary machinearchitecture. In another example, the bond head assembly could have anadditional motion axis along the x-axis, thereby enabling adjustmentsalong the x-axis, y-axis, and about the theta axis. In yet anotherexample, the support structure could have an additional motion axisalong the y-axis, thereby enabling adjustments along the x-axis andy-axis. Of course, many other exemplary architectures are possible.

In summary, and by reference to the exemplary architectures disclosedherein, after completing the alignment process (such as described abovein connection with FIGS. 3A-3H, 4A-4B, and 5A-5B) for all desiredregions of the substrate (e.g., all rows of bonding locations of thesubstrate)—the bonding of the semiconductor elements may begin. Forexample, in order to bond a given semiconductor device to acorresponding bonding location of a substrate, an imaging system (e.g.,system 174, which may include an up/down camera system to image aboveand below) may image the semiconductor element held by the place tool,and may image the bonding location, in preparation for bonding. Thisimaging provides placement information for the bonding of thesemiconductor element to the bonding location. However, additionaladjustments (dependent on the region of the substrate being bonded) tothe bonding tool and/or support structure positions may be made beforebonding in accordance with the present invention as described herein.After bonding of this semiconductor element, the process continues, withimaging of a subsequent semiconductor device and bonding location, etc.

While the present invention has been described largely in connectionwith a substrate (e.g., substrate 296) having rows and columns ofbonding locations, wherein the alignment is accomplished row by row, itis not limited thereto.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

What is claimed:
 1. A method of operating a bonding machine, the bondingmachine including a bonding tool configured to bond a semiconductorelement to a substrate, the method comprising the steps of: (a)providing an alignment structure on the bonding machine, the alignmentstructure including a plurality of first alignment markings; (b)selecting an area of the alignment structure based on a region of thesubstrate to be bonded with the semiconductor element, the substrateconfigured to be supported by a support structure of the bondingmachine; (b1) placing an alignment element, including second alignmentmarkings, on the area of the alignment structure using the bonding tool;(c) imaging ones of the second alignment markings on the alignmentelement along with ones of the first alignment markings on the area ofthe alignment structure; and (d) adjusting a position of at least one ofthe bonding tool and the support structure during a subsequent bondingprocess using information provided from step (c).
 2. The method of claim1 wherein the bonding machine is a thermocompression bonding machine. 3.The method of claim 1 wherein the region of the substrate includes a rowor column of bonding locations configured to be bonded with ones of thesemiconductor element.
 4. The method of claim 1 wherein the alignmentelement is at least partially transparent such that during step (c) theones of the first alignment markings are imaged with the alignmentelement being positioned above the area of the alignment structure. 5.The method of claim 1 wherein the alignment structure is secured to thesupport structure.
 6. The method of claim 1 further comprising the stepof holding the alignment element on the area of the alignment structureusing a holding force.
 7. The method of claim 6 wherein the holdingforce is provided by at least one of a vacuum force and a magneticforce.
 8. The method of claim 1 further comprising the step ofdetermining an adjustment of the position for use in step (d) with analgorithm using the information provided from step (c), the informationincluding relative positions of the ones of the first alignment markingsand the ones of the second alignment markings.
 9. A method of bonding aplurality of semiconductor elements to a substrate with a bonding tool,the method comprising the steps of: (a) placing an alignment elementover each of a plurality of areas of an alignment structure, each of theplurality of areas corresponding to one of a plurality of regions of asubstrate supported by the alignment structure; (b) determining anoffset of the alignment element with respect to each of the plurality ofareas; and (c) adjusting a position of at least one of (1) the bondingtool and (2) the support structure during bonding of a plurality ofsemiconductor elements to each of the plurality of regions of thesubstrate, the position adjustment for each of the plurality of regionsbeing related to the offset determined for the area corresponding toeach of the plurality of regions.
 10. The method of claim 9 wherein eachof the plurality of regions corresponds to at least one row of bondinglocations of the substrate.
 11. The method of claim 9 wherein each ofthe plurality of regions corresponds to at least one column of bondinglocations of the substrate.
 12. The method of claim 9 wherein step (b)includes imaging the alignment element over each of the plurality ofareas.
 13. The method of claim 9 wherein the alignment structureincludes first alignment markings and the alignment element includessecond alignment markings.
 14. The method of claim 13 wherein thealignment element is at least partially transparent such that ones ofthe first alignment markings of the alignment structure are visible toan imaging system when the alignment element is positioned over thefirst alignment markings.
 15. The method of claim 13 wherein the offsetof the alignment element is determined using relative positions of thesecond alignment markings from a corresponding portion of the firstalignment markings.
 16. The method of claim 13 wherein the secondalignment markings of the alignment element are configured to be alignedwith a portion of the first alignment markings of the alignmentstructure.
 17. The method of claim 13 wherein ones of the secondalignment markings include groups of markings, each of the groups ofmarkings being configured for alignment with a portion of the firstalignment markings.
 18. The method of claim 13 including the step ofaligning a portion of the second alignment markings with a correspondingportion of the first alignment markings based upon a size of a bondingarea of each of the plurality of regions of the substrate.
 19. Themethod of claim 13 wherein the first alignment markings are provided ona top surface of the alignment structure, and the second alignmentmarkings are provided on a bottom surface of the alignment element. 20.The method of claim 9 further comprising the step of providing aseparation between a portion of the alignment element and the alignmentstructure.
 21. The method of claim 9 further comprising the step ofapplying a holding force to hold the alignment element on each of theplurality of areas of the alignment structure.
 22. The method of claim21 wherein the holding force is provided by at least one of a vacuum anda magnetic force.
 23. The method of claim 9 wherein the alignmentelement comprises glass.